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By H. Rush Spedden, Arvid Thunaes

R. R. Knobler and F. E. Albertson—Following the testwork done by Thunaes and Spedden, a Sullivan deck plant was built for the Colquiri mill. This plant started to operate in April 1945 and continues in successful operation. Since May 1950 the Colquiri mill has operated with a completely revamped flowsheet at a rate of 1000 tons per day. The old Sullivan deck section was retained with this new flowsheet. The "slime plant" in Colquiri consists of one 12-cell Denver No. 18-Sp. Sub-A flotation machine, one 16-ft and one 12-ft hydroseparator, six five-deck Sullivan-frames and six shaking tables for cleaning up the Sullivan deck concentrates, as well as 12 Deister plus three Plat-O tables on which the fine sands, which are not treated on the S-decks, are concentrated. Only —325-mesh fines are treated on the Sullivan decks. The combined hydroseparator overflows are fed to the S-decks. From 1946 to 1949, i.e. with the "old" flowsheet and an average mill feed of 800 tons per day an average of 45 tons per day was treated on four Sullivan rougher frames. The two additional frames were used as cleaners. At times, up to 90 and 120 tons of slimes were treated successfully on this Sullivan deck installation. The average operating data for the S-deck section in Colquiri for the year 1949 were as follows: The tests reported in this paper indicated a tin recovery of 42 pct. The actual plant results for 1949 show a 54 pct tin recovery from the Sullivan decks. The total average quantity of tin produced from the S-deck section in 1949 was 15 tons of tin per month. This corresponds to 3 pct of the total mill recovery. The difference between the 6 pct overall recovery-increase expected after the tests in 1943 and the actual plant results given for 1949 is explained as follows. According to the tests, a total of 170 tons was expected to be routed to the Sullivan decks, but because of certain changes in the flowsheet and mill amplifications,

Jan 1, 1951

By W. J. Tait, A. E. Craig, E. P. McCurdy

C. M. Marquard—The problem of the automatic control of a grinding-classification circuit is not nearly as simple as has been indicated and it cannot be universally solved through the application of this device. The sound emanating from a ball mill such as the metallic clink of the balls against the liners can at times be misleading. The fact that the sound level due to the balls hitting the liners may be at a minimum does not necessarily mean that the mill is properly loaded. I have in mind an ore we treat that has a soft talcy gangue. The soft fluffy nature of this material makes the sound from the ball mill a most misleading parameter that is worthless as a means for controlling the amount of ore fed to the mill. In every milling plant there are transportation lags due to the time it takes the ore to travel from the mill bins to the ball mill. In many plants there may be several different transportation lags due to varying distances of bins from ball mill. These transportation lags can most seriously affect the operation of a controller. It has been found that under many circumstances the transportation lags can be so bad as to cause the controller to hunt seriously. Hunting can and in many cases does become so serious as to render automatic control impossible because of the surges it causes. While it is possible to compensate for this type of lag, this apparatus does not lend itself readily to accomplish the required compensation. Further, if there are groups of bins at various distances from the ball mill, compensation for one may not be sufficient or may be too great for another. Each milling plant presents a separate problem. The apparatus as presently described does not appear sufficiently flexible to accomplish this. It should be noted that the load on the classifier rakes is determined by measuring the current input to the rake drive motor. Variations in line voltage will

Jan 1, 1951

By E. P. McCurdy, W. J. Tait, A. E. Craig

C. M. Marquard—The problem of the automatic control of a grinding-classification circuit is not nearly as simple as has been indicated and it cannot be universally solved through the application of this device. The sound emanating from a ball mill such as the metallic clink of the balls against the liners can at times be misleading. The fact that the sound level due to the balls hitting the liners may be at a minimum does not necessarily mean that the mill is properly loaded. I have in mind an ore we treat that has a soft talcy gangue. The soft fluffy nature of this material makes the sound from the ball mill a most misleading parameter that is worthless as a means for controlling the amount of ore fed to the mill. In every milling plant there are transportation lags due to the time it takes the ore to travel from the mill bins to the ball mill. In many plants there may be several different transportation lags due to varying distances of bins from ball mill. These transportation lags can most seriously affect the operation of a controller. It has been found that under many circumstances the transportation lags can be so bad as to cause the controller to hunt seriously. Hunting can and in many cases does become so serious as to render automatic control impossible because of the surges it causes. While it is possible to compensate for this type of lag, this apparatus does not lend itself readily to accomplish the required compensation. Further, if there are groups of bins at various distances from the ball mill, compensation for one may not be sufficient or may be too great for another. Each milling plant presents a separate problem. The apparatus as presently described does not appear sufficiently flexible to accomplish this. It should be noted that the load on the classifier rakes is determined by measuring the current input to the rake drive motor. Variations in line voltage will

Jan 1, 1951

By H. Rush Spedden, Arvid Thunaes

R. R. Knobler and F. E. Albertson—Following the testwork done by Thunaes and Spedden, a Sullivan deck plant was built for the Colquiri mill. This plant started to operate in April 1945 and continues in successful operation. Since May 1950 the Colquiri mill has operated with a completely revamped flowsheet at a rate of 1000 tons per day. The old Sullivan deck section was retained with this new flowsheet. The "slime plant" in Colquiri consists of one 12-cell Denver No. 18-Sp. Sub-A flotation machine, one 16-ft and one 12-ft hydroseparator, six five-deck Sullivan-frames and six shaking tables for cleaning up the Sullivan deck concentrates, as well as 12 Deister plus three Plat-O tables on which the fine sands, which are not treated on the S-decks, are concentrated. Only —325-mesh fines are treated on the Sullivan decks. The combined hydroseparator overflows are fed to the S-decks. From 1946 to 1949, i.e. with the "old" flowsheet and an average mill feed of 800 tons per day an average of 45 tons per day was treated on four Sullivan rougher frames. The two additional frames were used as cleaners. At times, up to 90 and 120 tons of slimes were treated successfully on this Sullivan deck installation. The average operating data for the S-deck section in Colquiri for the year 1949 were as follows: The tests reported in this paper indicated a tin recovery of 42 pct. The actual plant results for 1949 show a 54 pct tin recovery from the Sullivan decks. The total average quantity of tin produced from the S-deck section in 1949 was 15 tons of tin per month. This corresponds to 3 pct of the total mill recovery. The difference between the 6 pct overall recovery-increase expected after the tests in 1943 and the actual plant results given for 1949 is explained as follows. According to the tests, a total of 170 tons was expected to be routed to the Sullivan decks, but because of certain changes in the flowsheet and mill amplifications,

Jan 1, 1951

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

ALABAMA Anniston.-Bretz, J A Carnngton, F G Gerber, A B Ashland -Barton J Sturdevant, J C Bessemer -Abbott, C E Ball, T L Ferguson, V Salmon, H S Schaber, C F Thompson, N E Whatley, W J Birmingham.-Adams, J H -Aldrich, T H Aldrich, T H , Jr ALASKA Anchorage -Dyer, B W. Parker, H C Smith, S S Chichagof.-Baumann, H N , Jr Copper River.-Douglass, W C Cordova.-Hazelet, G C Fairbanks -Davis, J A Hyder -Pitt, D L Juneau -Jackson, G. T Murphy, R E R..11 ti At i

Jan 1, 1923

NEW YORK SECTION J. E. Johnson, Jr., Chairman Edgar Rickard, Vice Chairman. D. M. Liddell, Secretary, 7 Wall St., New York, N.Y. C. A. Bohn, Treasurer John V. N. Dorr Lewis W. Francis. The annual meeting of the New York Section was held on Wednesday, June 6, with about 40 members in attendance. The treasurer re a brief summary of-the financial statement for the year, and the secretary&apos;s report was read. These reports were ordered placed on file together with the report of the auditors for the two previous years.

Jan 8, 1917

The Committee on Nominations will welcome from members of the Institute suggestions for the offices which are to be filled by election in February, 1018, and which are as follows: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and. VII of the Constitution, and to By-Law VIII, which reads as follows: "The geographical districts to he considered by the Committee on Nominations shall be as follows, until otherwise ordered by the Board.

Jan 8, 1917

By R. Schuhmann Jr., P. J. Ensio

John Chipman (Massachusetts Institute of Technology, Cambridge, Mass.)—The activity of FeO in silica-saturated slags shown in Table V is about 0.40 in the temperature range 1260" to 1350°C. Recent measurements by N. A. Gokeen at 1600" lead to about the same value. He finds the oxygen content of liquid iron in equilibrium with silica and ferrous silicate slags to be 0.088 pct. Under pure iron oxide slags at the same temperature, it is 0.225 pct. The ratio places the activity at 0.39.

Jan 1, 1952

YEAR OF ELECTION 1922. FEDERICO GIOLITTI Torino, Italy. 1917. HERBERT HOOVER Washington, D. C. 1941. DANIEL COWAN JACKLING San Francisco, Calif. 1939. HENRY KRUMB New York, N. Y. 1942. Essington Lewis Melbourne Vic., Australia 1921. C. McDERMID London, England. 1942. PAUL DYER MERICA New York, N. Y. 1913. EZEQUIEL ORDONEZ Mexico City, Mexico. 1938. A.M. PORTEVIN Paris France 1937. JOHN V.W. REYNDERS, New York, N. Y. 1937. GEORGE S. RICE Washington, D. C. 1911. ROBERT H. RICHARDS Cambridge, Mass. 1934. T.A. RICKARD Victoria, B.C., Canada

Jan 1, 1943

CHARLES KIRCHHOFF, Chairman. ALBERT SAUVEUR, Vice-Chair-man. A. A. STEVENSON, Vice-Chair-man. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Cambridge, Mass. John Birkinbine, J. Esrey Johnson, Jr., Felix A. Vogel, William H. Blauvelt, William Kelly, Leonard Waldo, James Gayley, Richard Moldenke, William R. Walker, Henry D. Hibbard, Joseph W. Richards, William R. Webster. Henry M. Howe, E. Gybbon Spilsbury, Frederick \V. Wood. Robert W. Hunt, A. A. Stevenson is appointed an additional Vice-Chairman of the Committee. He will serve as Acting Chairman during the absence abroad of Professor Sauveur.

Jan 7, 1913

By Joan Melcher

The oil embargo and increasing disillusionment with nu- clear power have put this country&apos;s abundant coal reserves in growing demand. Both the government and industry are looking toward increased coal mining, and with this goes an increased interest in new and advanced methods of coal utilization. One advanced coal system stands out among the rest-magnetohydrodynamics (MHD). Its high efficiency, strong probability of sulfur dioxide control, and limited consumption of cooling water place MHD in a unique position to help the power generation industry. Another point in MHD&apos;s favor is the capital costs of operation, which are lower than those of other advanced technologies. However, initial costs are higher and realization of a commercial MHD plant in this country may be more than a decade away.

Jan 12, 1977

By P. F. MINISTER

AT Lime Spur, Mont., the East Butte Copper Mining Co. has been quarrying limestone for twenty years. The quarry is beside the Northern Pacific R. R. in the Jefferson River canyon, 4 ½ miles east of Cardwell, at Lime Spur, Montana. HISTORY This quarry was opened early in 1900 by Dan Morrison of Whitehall, the discoverer of the Morrison cave, to supply a demand for smelter flux. Limestone was sold to the Pittsmont smelter of The East Butte Copper Mining Co. and to the Butte Reduction Works. As no particular effort was made at the quarry to select the rock that delivered to the smelters was unduly high in magnesia and impurities. The East Butte com¬pany, therefore. Bought the quarry. in 1909 and confined operations to the high-grade beds in order to supply rock of the desired purity for its own smelter and the Butte Reduction Works until the latter shut down. It also developed a market for some of its rock with the sugar factories. The latter market increased until in later years all rock, larger than 4 in. in size over a bar grizzly, was being shipped to the sugar factories, and the rock smaller than 4 in. was being used as a flux in the blast furnaces at the Pittsmont smelter. In 1924, the East Butte concluded a contract with the Anaconda company for the treatment of its ores, and the Pittsmont -smelter -was shut down: which made the minus 4-in. rock a useless by-product. Since there was not enough revenue in the sugar rock alone and also because of limited waste room it became necessary, if Lime Spur was to continue to operate, to increase- the proportion of plus 4-in. rock and to develop a market for the minus 4-in.

Jan 1, 1930

By Charles M. Rolker

(Read at the Philadelphia Meeting, February, 1878.) THE Mariposa estate, a grant made by the Mexican Government to Juan B. Alvarado, during the time when California was still under the dominion of Mexico, was purchased in 1847 by J. C. Fremont, and the United States patent issued to him in 1856. By sale, or its equivalent, money advanced, the property came into the hands of the Mariposa Company, June 25th, 1863, and through a varied existence of work and temporary inactivity, has as yet been kept as an undivided property, and rests at present with the Mariposa Land and Mining Company of California. I pass over this period of 15 years without giving the history of the ups and downs of the estate, partly because it is familiar to many, and also because I think in such a case this paper would assume too much the character of a narrative. The estate is situated in Mariposa County, California, about 170 miles southeast of San Francisco. It begins in lat. 37° 26’ 38" - north, and long. 119° 55&apos; west, and runs 6 miles north; thence 6 1/2 miles west; thence 5 miles northwesterly towards the Merced River; thence 8 1/2 miles southerly; thence 3 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 2 miles southerly; thence 2 miles easterly; thence I mile southerly; thence 2 miles easterly; thence 1 mile northerly, and thence 2 miles easterly to the place of the beginning; embracing 44,387 acres (70 sq. miles) more or less. To describe this vast estate in detail as to its full geology, its numerous quartz veins, its many facilities to exploit them and work them by cheap methods, would lead me further than I intend to go at present, and I will content myself to describe the latest workings of the company and its immediate field of operations. As long ago as 1860 the late Dr. Adelberg advised the running of an adit from the northwestern edge of the estate at Benton Mills on the Merced River. His object was to undercut the deepest workings of the then paying mines on the estate-the Pine Tree and Josephine. Following this advice, the tunnel known as "River Tunnel" was commenced. Its entrance is in S. 5, T. 4, S. R. 17 E. It is run in

Jan 1, 1878

By Earle C. Waite

THE Industrial Minerals Division this year held no individual sessions of its own except the business meeting Tuesday afternoon. One session was held jointly with the Society of Economic Geologists, one with the Milling Methods Committee, and two with the Society of Economic Geologists and the Mining Geology Committee. At all of these meetings the attendance was better than usual and the Tuesday afternoon session, with nearly 400 present, probably set a new record for the Division. Joint sessions seem extremely popular when papers of mutual interest are presented. On Monday afternoon, mica was the predominating subject. The North Carolina mines provided most of the information presented, although the discussion brought out similarities with the New England mines. B. C. Burgess particularly stressed the fact that with the existing curtailment of mica from India it is necessary to get the most mica in the shortest time from the mines in this country. He said that the Colonial Mica Corp. hopes to have 1000 mines operating in the near future. This seems a great number, but when one considers that these mines employ from 3 to 28 men, mostly nearer the low figure, the output of each mine is relatively small. Although the price of mica is from six to ten times the prewar price, the yield of 8 to 150 lb. of mica per ton of raw ore does not provide high returns to the producer.

Jan 1, 1943

By James K. Richardson

Today, the enigma of the "missing man" in the metal mining industry equals, and frequently surpasses in objective importance, the problems of ore development, drilling, sampling, pumping, milling techniques, geophysical prospecting, or any one of a hundred highly technical subjects. Unfortunately, as engineers, we have confined our attentions, in the main, to the scientific phases of mineral technology, relegating our man power problems to the background. But what good has all our scientific study and preparation been if we can&apos;t get the ore mined, milled, or smelted? What has happened to our labor supply? Where is the good old miner who could timber, drill a round, lay track, or do any job underground?

Jan 1, 1949

By M. Garfinkle

LITERATURE data1&apos;3 have suggested that the resolved shear stress necessary to initiate slip in a particular slip system in tungsten single crystals is strongly dependent on the tensile orientation of the crystals. This orientation dependence is contrary to the critical resolved shear stress criterion. Because the Schmid factors for slip on particular {110}( I l l), {112}(Ill), or {123}(111) slip systems in a (100) oriented tungsten crystal are virtually identical to the respective Schmid factors for a (110) oriented crystal, slip should initiate on the same system in both orientations, independent of the values of the critical resolved shear stresses. Thus, it would be expected that, for a critical resolved shear stress model to hold, the proportional-limit stress for these two orientations must be similar. The expectation of similar proportional -limit stresses has not been borne out by reported experimental observations. Rose et nl.&apos; reported that the proportional-limit stress for crystals near the (110) orientation was 92,000 psi, approximately three times that of (100) oriented crystals (31,000 psi). Garlick and probst2 reported greater than a fourfold difference. Most recently, Beardmore and ~ull~ examined tungsten crystals with orientations along the edge of the standard stereographic triangle and showed a gradual increase in proportional-limit stress from 28,000 psi for the (100) orientation to 93,000 psi for the (110) orientation. Again, the difference was more than threefold. As has been emphasized by these investigators, the apparent gross variation of proportional-limit stress with orientation precludes any meaningful analysis of slip mechanics using a simple critical resolved shear stress relation. The purpose of the present communication is to report that, by use of refined strain-measuring techniques, the proportional-limit stresses for the (100) and (110) orientations are quite similar. Obviously, to determine accurately the value of the proportional-limit stress, which is by definition the stress at which nonlinear stress-strain behavior first occurs, the method of measuring strain must be capable of high accuracy. The investigators cited used as the measured elongation the crosshead displacement of the tensile machine. This method, however, introduces extraneous strain contributions from the load train. Because these extraneous contributions are considerable in the initial portions of loading (as has been well-documented in the literature) the proportional-limit stress measurement, dependent on the deviation of a line from linearity, can be significantly affected. During the course of a recent study, room-temperature strain was measured directly on several (100)-and (110)-oriented tensile specimens axially oriented within 5 deg of the desired direction. Each specimen was fitted with two foil strain gages mounted on opposite sides of the 0.08-in.-diam reduced section. The tensile specimens were loaded at a crosshead speed of 0.01 in. per min on an Instron Universal Testing Machine. Strain was monitored through an external bridge circuit in which the specimen strain gages comprised two arms. The bridge output was recorded against the applied load. A strain of 2 x 10"" could be readily detected by this method. Some specimens were subjected to conventional loading while the load for others was cycled between zero and continually increasing values until the first deviation from linearity was observed. The results of these methods were similar, and the stress at which nonlinear behavior occurred was considered the proportional-limit stress. The proportional-limit stresses measured in this study are approximately 5000 and 6500 psi for the ( 100) - and ( 110) -oriented crystals, respectively, a range of values almost a magnitude less than those reported previously. Representative curves are presented in Fig. 1. Because of the nature of the measurements made, the point of departure of a line from linearity is often debatable. While the load-strain curve for the (100) -oriented crystals made a relatively abrupt deviation from linearity, the curve for the (110) -oriented crystal was more gradual, so that the actual point of tangency may be at a lower load than reported. Thus, the difference in values for the proportional-

Jan 1, 1967

By Paul T. Benson

MOST important of the various departments of a custom smelter, so far as the financial welfare of the plant and the confidence of shippers are concerned, is that responsible for correct weights, accurate moisture sampling, and the obtaining of control samples that are strictly representative of the lot of ore from which they come. Treatment rate schedules are based on the metal content of ores received, reduced to dry weight. These rates must be low enough to keep the ship- per from taking his business else- where and still must allow the smelter a profit. Assay results, likewise, must satisfy the shipper, but if they show too high a metal content for the ore they represent, the smelter will actually lose money. It is always considered, and constant checks through umpire assays prove, that laboratory results are closely correct, so the bur- den of the plant profit and loss and the satisfaction of the shipper rest squarely upon the sampling department.

Jan 1, 1936

By B. D. Saklatwalla

FOR the proper understanding of the inclusion of certain elements in this review it seems necessary to state the meaning of "rare metals." Certain elements occur in deposits limited in extent or concentration, so that the extraction of the element in relation to market conditions becomes uneconomical. Others may occur in extensive and rich deposits but the reduction of the metal may be difficult and costly. Both these conditions effect the same result, namely, make the metal rare and costly. As an example of the first kind may be mentioned radium and of the second, calcium.

Jan 1, 1939